Film transport system for photographic cassette having self-contained film processing system

ABSTRACT

A film transport system for a film cassette comprising a strip of film and containing a film processing system. The transport system effects a programmed sequence of movements of the film by driving a reel to which the film is connected at constant linear speed relative to the processing system with a drive motor supplied with a control signal decaying at a predetermined rate.

United States Patent 11 1 1111 3,809,327

()sman May 7, 1974 1 1 FILM TRANSPORT SYSTEM FOR [56] References Cited PHOTOGRAPHIC CASSETTE HAVING UNITED STATES PATENTS SELF-CONTAINED FlLM PROCESSING 3,704,401 11/1972 Miller 242/7551 x SYSTEM 2,991,950 7/1961 Axon et al. 242/187 3,634,744 l/l972 Toensing et a1. 242/191 X [75] Inventor M Osman Newton 3,615,127 10/1971 Land 352/130 x Hghland Mass' 3,412,668 11/1968 Buckingham 95/89 R x [73] Assignee: Polaroid Corporation, Cambridge,

Mass. Primary Examiner-Fred L. Braun [21] Appl. N0.: 227,169 A film transport system for a film cassette comprising a strip of film and containing a film processing system. The transport system effects a programmed sequence [52] "1242/71? of movements of the film y driving a reel to which [51] Int Cl (503d 5/00 the film is connected at constant linear speed relative [58] Fie'ld 242/75 51 to the processing system with a drive motor supplied with a control signal decaying at a predetermined rate. 3 Claims, Drawing Figures 205 53 20a Kl g? /6 I 82 14 d 209 (y 59 I Z/0 /2 DI SM I 2//- 5 CONTROL I SYSTEM 203 7 lg, 3 5 5 3 d d 31 ST so SP SR MR 50 SE l- 3 SF 1 1 CKI DCM c1 2 PATENTED I" 7 I974 SHEET 3 [IF 9 PATENTEDIAY 1 I974 SHEET t [If 9 WNT W UQK m3 km QQ mw m8 mm EX NS MN Q PATENTEDMAY 7 I974 SHEETS UF 9 DESIRED PATENTEDIAY 7 1914 I SHEEI 7 OF 9 FILM TRANSPORT SYSTEM FOR PHOTOGRAPIIIC CASSETTE HAVING SELF-CONTAINED FILM PROCESSING SYSTEM This invention relates to photography, and particularly to a novel speed control system for processing strip film.

A widely accepted advance in the photographic art has been the creation of photographic systems in which photosensitive material is packaged with processing composition so that photographs may be produced without the aid of a darkroom immediately after the production of a latent image in the camera. It has been proposed to extend this facility to the production of projection transparencies, as for motion pictures and the like.

Toward this end, a novel photographic system has been conceived which comprises as the key element a replaceable film cassette. The cassette contains a strip of film, a supply of processing composition for the film, and an internally programmed processor responsive to the manipulation of the film in the cassette for applying the processing composition'to the film after its exposure. I

The cassette is adapted to be inserted in a camera, for

exposure of 'the film. After exposure, it is inserted into a film drive and projection system. This system comprises a receptacle configured to receive the cassette, and cyclic drive apparatus for manipulating the film in the cassette. The film is manipulated in a sequence determined by a signal provided by the cassette that indicates whether or not the film has been processed.

In response to the insertion of a cassette containing unprocessed film, the film drive and projection apparatus manipulates the'film in the cassette in a lighttight environment. That movement of the film activates the processor, developing the film to produce a series of fixed, visible, projectable images. Thereafter, the apparatus manipulates the film in an optical system, causing it to be projected for viewing. Finally, the film is rewound, for storage and subsequent reuse. In response to the insertion of a'cassette containing processed film, the system simply projects the film, and then rewinds During the processing of the film, an initially sealed container of processing composition is opened, and allowed to flow by gravity into a coating nozzle. It is then desired to coat the composition in a uniform thickness on the film, while moving the film past the coating station onto a storage reel.

Two problems are presented by the requirements for processing. First, it is highly desirable to use as much as possible of the film strip for the production of projectable images, and as little as possible for control and handling purposes. Second, it is manifestly important to treat the film uniformly throughout its length. To some extent, variations in process conditions, such as the speed of the filmpast the coating station, can be compensated for by the construction of the film coating apparatus, as will appear. However, other conditions, such as the time spent by the coated film in transit from the coating station to the storage reel, may affect the quality of the processed images if allowed to vary. The objects of the invention are to facilitate the uniform processing of strip film in a cassette containing a film processing system, while improving the quality of the processed images and reducing the quantity of film needed for purposes other than the production of projectable images.

Briefly, the above and other objects of the invention are attained by a novel film processing system comprising means for transporting the film past a processing station in accordance with a predetermined program that ensures efficient utilization of the film while maintaining uniform process conditions. To that end, a film drive system is provided which operates in three stages during the portion of the film processing cycle in which the film is drawn past the coating station.

In the first stage of operation in accordance with the invention, a short length of film is drawn past the processing station in the opposite direction from that in which the film was exposed. That movement of the film is used to open the initially sealed container of processing composition.

Next, film motion is stopped for a short interval. This pause is provided to allow the processing composition to complete its passage into the reservoir above the coating aperture, without requiring unused film to be transported before the nozzle is prepared to coat it uniformly.

Finally, the film is transported past the coating station while the processing composition is applied to it. During this step, the film is wound onto a storage reel. The rate at which the film moves is determined by a number of variables, including its mass, density and thickness, the dynamics of the storage reel on which it is wound, and the radius of the coil of film on the storage reel as a function of the amount of film that has been processed. In accordance with the invention, the film storage reel is driven by an electric motor under thecontrol of a novel control circuit which compensates for the effects of these variables to cause the film to move at substantially constant linear speed past the coating station. By that arrangement, the film is processed'uniformly over the entire photographically usable portion.

The apparatus of the invention, and its mode of operation, will best be understood in the light of the following description, together with the accompanying drawings, of a preferred embodiment thereof.

In the drawings,

FIG. 1 is a schematic perspective sketch of a cassette adapted for use. with the invention;

FIG. 2 is a schematic perspective sketch of a film drive and projection system suitable for use with the cassette of FIG. 1;

FIG. 3 is a schematic cross-sectional elevation of the film drive and projection system of FIG. 2, taken substantially along the lines 3-3 in FIG. 2;

FIG. 4 is a fragmentary schematic plan sketch, with parts broken away, of a film strip forming a part of the cassette of FIG. 1;

FIG. 5 is a schematic plan sketch, with parts omitted, parts shown in cross section and parts broken away, of a film cassette in accordance with the invention;

FIG. 6 is a fragmentary schematic perspective sketch, with parts broken away and parts shown in cross section, of a portion of a composition release mechanism forming a part of the apparatus of FIG. 5;

FIGS. 7 and 8 are schematic fragmentary crosssectional elevational views, with parts shown in cross section and parts broken away, of further details of a portion of the release mechanism of FIGS. 5 and 7, taken substantially along the lines 77 in FIG. 5, with parts shown from position taken somewhat behind those lines, showing the parts in two positions and in association with a portion of a detent release mechanism forming a part of the film drive and projection system of FIG. 2;

FIG. 9 is a schematic fragmentary plan view, with parts shown in cross section, parts omitted and parts broken away, showing the apparatus of FIG. in another position assumed during its operation;

FIGS. 10, 11 and 12 are fragmentary schematic plan views, with parts shown in cross section, parts omitted,

and parts broken away, showing on an enlarged scale the sequence of operation of processing apparatus forming a part of the apparatus of FIG. 5;

FIG. 13 is a schematic perspective sketch of a pressure pad forming a part of the apparatus of FIG. 5;

FIG. 14 is a schematic perspective sketch of a coating nozzle forming a part of the apparatus of FIG. 5;

FIG. 15 is a schematic cross-sectional elevational view of the nozzle of FIG. 14, taken substantially along the lines 15-15 in FIG. 14;

FIG. 16 is a schematic perspective sketch of a pressure pad depressing cam and nozzleclosure plate assembly forming a part of the apparatus of FIG. 5;

FIG. 17 is an elevational view of the apparatus of FIG. 16, taken substantially along the lines 17-17 in FIG. 16; l

FIG. 18. is a schematic block and wiring diagram of the film cassette of FIG. 1, ShOWI'l3iIl, association with control apparatus forming a part of the film drive and projection system of FIG. 2;

FIG. 19 is a schematic block and wiring diagram showing further details of the control system for the film drive and projection system of FIG. 2 and FIG. 20.is a graph of voltage versus time comparing an ideal voltage decay characteristic with an actual voltage decay characteristic obtained in the apparatus of the invention.

FIG. 1 shows the external aspects of a cassette 1. Referring to FIGS. 1 and 2, the cassette 1 is adapted to be inserted in a pocket 2 formed in the outer housing 3 of a filmdrive and projection system. As schematically indicated, a cover 4, hinged to the housing 3 as suggested at 24, may be provided to forma light-tight housing about a cassette 1 when the latter is inserted in the pocket 2. A translucent viewing screen 5,'on which projected images at times appear, is mounted at the front of the housing 3.

As shown in FIGS. 2 and 3, the pocket 2 has a floor 6 on which an aperture plate 7 is mounted. The aperture plate 7 is adapted to extend into a recess 25 formed in the cassette 1, and there register with a strip of film 26 in the cassette. Light supplied to thecassette in a manner to be described passes through the film, and thence over a path traversing a suitable framing aperture in the aperture plate 7, a cooperating recess in the floor 6, a blinder housing 8, to be described, and a conventional shutter 9, to a lens 10. The lens focuses an image of the portion of the film selected by the framing aperture on a mirror 11, whence it is reflected to the screen 5. 1

As suggested in FIG. 1, the cassette 1 is provided with a number of light-baffled openings 12, 13, 14, 15 and 16. These openings expose parts adapted to cooperate with corresponding parts of the film drive and projection system to perform various functions in the cassette. Thus, a drive sprocket formed on a film takeup reel in the cassette is accessible through the opening 12. A similar drive sprocket formed on a supply reel in thecassette is accessible through the opening 13. Projection light is at times'admitted to the cassette through opening 14. The opening 16 serves to admit a locating pin, forming a part of the film drive and projection system, to register the presence of a cassette in the system and to enable the processing apparatus in a manner to -be described. A stop can enter, to brake asnubber roll forming a part of the cassette, through the opening 15.

A flange 17 is formed on the upper end of the cassette 1. This flange aids in grasping the cassette while inserting it in, or removing it from, the pocket 2. It also helps to fix the cassette in position in the film drive and projection system, by engagement with the rim of the pocket 2.

Referring to FIG. 3, parts adapted to enter the openings in the cassette 1 are adapted to enter the pocket 2 through corresponding openings in a side wall 18 of the pocket. Drive sprockets for the supply and takeup reels are adapted to enter through openings 19 and 20, respectively. A light beam for projection enters through an opening 21. The locating pin enters through an opening 22. The snubber roll stop enters through an opening 23.

The photographic system of the invention preferably makes use of a photofinishing process in which a strip vof film, following exposure in the camera, is contacted witha single processingcomposition to form a finished transparency from the latent image or images formed on the film during its exposure. The physical construetion of such film, the nature of the photosensitive coating thereon, and suitable processing compositions therefor, will next be discussed in connection with FIG.

Referring to FIG. 4, there is shown a film strip generally designated 26, which comprises a leader 27 terminating at any end formed with an aperture such'as 28. The aperture 28 serves to connect that end of the film to a takeup reel, to be described.

Behind the leader, which may be in the neighborhood of 18 inches in length, there is a strip 29 of photographically useful film, upon which projectable images may be formed. The strip 29 may be, for example,'approximately 52 feet in length for 8 mm. film.

Following the photographically useful portion of the film is-a-trailer region generally designated 30. The trailer 30 terminates at another end formed with an aperture 35 by means of which that end of the film is adapted to be connected to a supply reel, to be described.

The film 26 may comprise a base of any suitable transparent material of the kind conventionally used for film bases. On this base is applied, at least over the central portion of the photographically usable length of the film 29, an emulsion comprising a photosensitive coating, vwh ereon a series of latent images illustrated by a series extending from a first frame 36 to a last frame 37 may be formed with a camera. The photosensitive coating is preferably of one of the forms, next to be described, which can subsequently be processed to form a projectable image on the film base.

Photosensitive coatings usable in the practice of the invention may be of any conventional variety adapted to be developed by a monobath processing composition to form a positive transparency suitable for projection.

In particular, a currently preferred embodiment of the invention makes use of a film structure which, upon the base, comprises a photosensitive layer including both a photosensitive negative emulsion and an imagereceiving layer to which a positive image may be transferred by diffusion during development without necessitating the subsequent removal of the emulsion containing its developed negative image. This highly desirable feature is made possible by a developed negative image having low covering power.

In typical silver transfer reversal processes for the projection of black and white images, a silver halide developer and a silver halide solvent are applied in an aqueous alkaline solution to a photoexposed silver halide emulsion stratum, where they develop exposed silver halide to silver, and react with unreduced silver halide to form a soluble silver complex. This complex, in order to form a positive print, is transferred and reduced to silver on a silver-receptive stratum upon which the silver halide stratum has been superposed.

In one practice, in the completion of this process, the silver-receptive and silver halide strata have been separated in order to render the positive print visible. However, as indicated above, the positive print may be rendered visible without separation of the silver halide and the silver-receptive strata. For example, the silverreceptive stratum may be so constructed as to provide an unusually vigorous silver precipitating environment which causes the silver deposited upon it, in comparison with silver developed in the silver halide stratum, to possess very high covering power, i'.e., opacity for a given mass of reduced silver. If the silver halide is in such a concentration as to give rise only when fully developed to a predetermined low maximum density, and if the silver complex is reduced to silver in a vigorous silver precipitating environment, the resulting negative and positive prints in superposition provide a composite print that presents a good image for projection purposes so long as they are contained on a transparent support. Since the silver halide stratum and the silverreceptive stratum need not be separated, an overall simplification of the silver transfer reversal process is achieved.

A composite film assembly of this type, as well as processing compositions for producing a fully developed black and white image without the necessity of removing the developed negative image after processing, are shown in prior US. Pat. No. 2,861,885 to Edwin H. Land, which issued on Nov. 25, 1958, for Photographic Processes And Products. Other composite film assemblies capable of producing developed full color images without the necessity of removing the developed emulsion are shown in prior US. Pat. of Edwin H. Land, Nos. 2,726,154, issued Dec. 6, 1955 for Photographic Product, and 2,944,894, issued July 12, 1960 for Photographic Processes Utilizing Screen Members.

It should be noted that the invention is not directed to the chemistry by which images are developed in a photosensitive emulsion and transferred to an imagereceiving stratum. However, in the practice of the invention, whether the film employed is black and white or color film, at the present time the preferred embodiment of the invention employs film of a type not requiring the removal of a negative emulsion after it is developed.

Referring again to FIG. 4, the film 26 is formed along one edge with sprocket holes such as 38 at regular intervals adapted to cooperate with a drive pawl, in a manner to be described, in either camera or projector, for incremental advancement of the film. The series of sprocket holes 38 adjacent the trailing end of the film may be interrupted by a first elongated sprocket hole 39. This elongated hole 39 may span, for example, two of the sprocket holes 38.

Further along the film in the direction of the supply reel end, the series of sprocket holes 38 is again interrupted by a second elongated sprocket hole 40, longer than the sprocket hole 39 and, for example, spanning three of the sprocket holes 38. As will appear, the first elongated sprocket hole 39 establishes an exposure end point in the camera, whereas the second sprocket hole 40 determines a film takeup termination point in the film drive and projection apparatus to be described.

Basically, termination of film advance at the first elongated sprocket hole 39 is attained by the use of a single drive pawl in the camera, which sequentially engages the sprocket holes 38 to advance the film by one frame length in a conventional manner. Toward the end of each such advance stroke, as is conventional, the pawl is cammed down out of engagement with the film. When the single-pawl engages the elongated aperture 39, the camming down movement occurs before the film engages the leading edge of the elongated hole, and therefore the pawl may cycle repeatedly without further advance of the film. This serves to effect a termination of film advance for the purposes of exposure adjacent the end of the region of photographically useful emulsion, to alert the photographer, by the somewhat different sound produced when the pawl skips the film, that his cassette should be replaced.

The film drive and projection system is provided with a double pawl, comprising two integral pawls spaced apart by one frame length, each pawl being of the same shape as the single pawl in the camera. When the first elongated aperture 39 is encountered, the leading pawl of the pair serves to engage the leading edge of the aperture 39 to cause the film to be advanced without interruption. For normally spaced sprocket holes 38, both of the pawls engage the film in sequential sprocket holes. However, when the second elongated sprocket hole 40 is encountered, the pawls will pass through it without film engagement, and thereby terminate film advance in the same manner as did the single pawl upon engagement of the double length sprocket hole 39.

Formed on the trailing end 30 of the film 26, beyond the exposure advance termination portion just described in the direction of the supply reel end of the film 26, is a singularity generally designated 41 comprising a detent engaging element here shown as an aperture 42 formed in the film, adjacent which a projecting bump 43 is formed, as by pressure, heat and pressure, or the like. The singularity 41 thus comprises a hook adapted to engage a detent in the form of a process control actuating element, to be described, as the film is moved with respect to the detent in the direction of the takeup reel.

The bump 43 forming a part of the detent engaging assembly 41 in FIG. 4 projects from the film, and might be deformed, or might cause pressure marks on other parts of the film, as it is wound on the reel. To avoid that result, it is preferred to provide suitable pockets,

not shown, comprising apertures formed in the trailing end 30 of the film, and spaced at suitable intervals with respect to the radius of the supply reel spool, to be described, to receive the projection 43 as the film is wound onto the reel. This provision allows the film to be evenly wound on the spool, without deformation of the bump.

Formed on the leader end 27 of the film 26 is another detent engaging means, here shown as an aperture 44 in the central region of the film. This aperture serves to actuate a valve member forming a part of the processing apparatus to be described, for purposes to apperar.

FIG. shows, in part fragmentarily and in part schematically, the pertinent elements of an internally programmed cassette 1 adapted for use in the system of the invention. The cassette comprises a housing formed of any suitable opaque material such as metal, plastic or the like, and preferably manufactured in two cooperating parts.

As shown in FIGS. 5 and 6, the housing parts comprise a base generally designated 45, comprising side walls 46 and a base plate 47. The base plate 47 extends across the base of the walls 46, and comprises one side of the housing. The walls '46 extend at least in part about the periphery of the base plate 47, and cooperate with interfitted walls 48 of a cover generally designated 49. Thewalls 48 overlap the corresponding segments of the ,walls 46 to form the sides of the housing of the cassette 1. i i

A cover plate 50 is formed integral with the walls 48, and completes the upper side of the housing as seen in FIG. 6. The terms base, cover, upper" and lower are relative, and are adapted simply for convenience. Similarly, the selection of the parting lines between the walls 46 and 48 is a matter of convenience. In particular, the choice is preferably so made that the base 45 can serve as a support upon which all of the additional fixed and moving parts to be described may be assembled before the cover 49 is put in place.

When the cover is placed in position, it may be I formed integral with thebase by heat sealing, or by a suitable adhesive, or the like. If of metal, the interfitting parts may be interlocked with cooperating detents formed" therein, ,in a manner conventional and well known to those sk illed'in the art.

The base and cover parts form, when assembled, the end'flange 17 that serves to support and locate the eassette l in either a camera, or in the film drive and projection system of FIG. 1.

Rotatably disposed within the cassette housing is a supply reel generally designated 51. The reel 51 is provided with an upper flange 52 and a corresponding lower flange, not shown in FIG. 5, to guide the film strip 26 as it is wound about the spool portion of the reel 51, not shown, to which the supply end 30 of the film 26 (FIG. 4) is attached.

A sprocket schematically indicated at 53 may be formed integral with the reel 51 to adapt the reel to be driven about its axis of rotation. Access to'the sprocket 53 may be provided through the aperture 13 in the cover plate (FIG. 1), light-baffled by suitable conventional annular flanges, not shown, formed in cooperating relation on the cover plate 50 and on the upper surface of the flange 52 (FIG. 5). The lower flange of the reel 51 may be formed in a conventional manner with a cylindrical axial opening to receive a cooperating axle, not shown, formed integral with the base plate 47.

A hub 54, formed integrally with the base plate 47, serves as a bearing for an arm 55 that is rotatable in the housing about the axis of the reel 51. The arm 55 forms part of a composition release mechanism, to be described.

Initially, the film 26 is in its unexposed state and coiled primarily about the supply reel 51. It is shown in FIG. 5 in the position assumed as it nears the end of its movement away from the supply reel, as toward the end of exposure in a camera, in which it is nearly exhausted from the reel 51.

In its path from the supply reel 51, the film 26 first encounters a bobulator roll 56. The film engages a portion of the periphery of the bobulator roll, as shown, and passes therefrom around a conventional idler roll 57 journalled for rotation in the housing, and thence through film processing means, to be described below. In addition to the apparatus for processing the film in a manner to be described, the film processing means comprises a signal generator for producing an external condition signal on terminals schematically indicated at 58 and 59, to indicate whether or not the processing, means has been actuated. V

Beyond its path through the film processing means, the film 26 extends through a conventional lightbaffled aperture schematically indicated at 60 and "forming a portion of a film gate in the housing. The film 26 reenters the housing through a second light-baffled aperture generally designated 61 and comprising a second portion of thefilm gate.

The film 26 next passes over a conventional snubber roll, generally designated 62, and finally passes to a takeup reel generally designated 63, comprising a spool portion to which the takeup re'el end of the film is connected, and about which the film is wound as suggested in FIG. 5.

In addition to parts corresponding to those parts described in connection with the supply reel 51, tha takeup reel comprises an external upper flange 64 protruding beyond the maximum radius of the film 26 when substantially stored on the takeup reel. On the flange 64 is formed a suitable drive sprocket 65, by meansof which the filmcan'be selectively-advanced in a manner to be. described.

The bobulator may be of any conventional construction suitable for the performance of the known function of isolating the film drive pawl associated with the camera, or thepawl associated with the projector, from the inertia of the supply reel 51. However, it is preferably of the form shown, in which the bobulator roll 56 is journalled on a pin 66 for rotation by the film.

The pin 66 is formed integral with a support 67 of plastic or the like. The support 67 is journalled to the base plate 47 by means of a pin 68 formed integral with the base plate, and biased by a spring 69 formed integral with the support 67. The spring 69 acts against a post 70 formed integral with the base plate 47. The bobulator roll-56 can thus both rotate about the pin 66, and move backwards and forwards in the directions of the double arrow shown in FIG. 6.

The bobulator roll responds to increases or decreases in the tension of the film 26 by temporarily shortening or lengthening the film path, respectively. Such changes in film tension are produced by the actuation of the film drive pawl, and are determined by the inertial forces exerted by the supplyreel 51, together with the larger or smaller supply of film that may be on it at any given time. By that arrangement, as the film is advanced incrementally by the pawl associated with the camera or projector, it can rapidly move the bobulator roll against the spring 69 without immediately affecting the supply reel, which can then more or less gradually allow the bobulator roll to relax while supplying the segment of film taken by the pawl.

A light-tight shield around the film gate formed by the apertures 60 and 61 is formed by a wall portion 75, formed integral with the base plate 47, and made integral with the cover plate 50 after assembly of the parts in the manner described above. An exposed chamber behind the film 26 is thus formed for the purpose of admitting projection light.

The apparatus for this purpose is conventional, and will only briefly be described. In short, it comprises a prism generally designated 76 and comprising a mirror, not shown, but disposed at 45 to the plane of FIG. 5. As schematically indicated, the prism 76 is mounted between extensions 77 formed on the wall 75.

Light enters the cassette through the port 14 formed in the cover plate 50 in directions normal to the plane of FIG. 5. The mirror in the prism 76-directs' this light downwardly through the film 26 in the film gate for the projection of images on the film through the lens (FIG. 3).

Also disposed in the chamber bounded by the wall member 75 and the film passing through the film gate is a conventional pressure plate 78, locatedbetween the prism and the film, and biased by a spring 79 into engagement with the film. The spring 79 is supported and retained by suitably shaped'extensions 80 of the support wall 75, as shown.

The pressure plate serves in the conventional manner to cooperate with a camera, by locating the focal plane of the film during exposure. An aperture 81 is provided in the pressure plate 78, as schematically indicated, to pass light entering through the prism assembly 76 through a selected frame of the film 26, after the film is processed in a manner to be described. It is preferred that the aperture 81 be somewhat larger than the frame to be projected so that the aperture in the aperture plate 7 (FIGS. 2 and 3) serves as the limiting aperture bounding the projected frame.

The snubber roll 62 may also be of entirely conventional construction. As illustrated, it is provided with a hub portion schematically indicated at 82 that is adapted to protrude through the (suitably light baffled) aperture 15 in the cover panel 50 for engagement by a stop member, comprising a part of either the camera or of the film drive and projection system, that is engaged when the film is to be incrementally advanced by a pawl for exposure or projection purposes. The cooperation between the snubber roll 62 and the takeup reel 63 is conventional, but will be briefly described.

The drive sprockets 53 and 65 of the supply and takeup reels 51 and 63, respectively, are adapted to be engaged by corresponding drive sprockets'comprising a part of a camera, or of the film drive and projection apparatus to be described. In the film drive and projection apparatus, both supply and takeup reels are adapted to be driven through slip clutches. In the camera, only a drive for the takeup reel need be provided. This drive comprises a slip clutch connected to a sprocket driving the takeup reel drive sprocket 65, in

cooperation with a drive pawl for sequentially engaging a series of the sprocket holes 38 formed in the film 26, along a portion of the edge of the film in the film gate between the apertures 60 and 61.

When the snubber roll 62 is stopped by engagement of the hub 82 as described above, operation of either the camera or of the film drive and projection system to incrementally advance the film towards the takeup reel, by engagement of a pawl with the sprocket holes in the film 26, will momentarily loosen the film from engagement with the stationary snubber roll 62 and allow the slip clutch driving the takeup reel 63 to take up that increment of the film advanced by the pawl. Between engagements of the pawl, the slip clutch prevents the takeup reel from advancing the film.

In the film drive and projection system to be described, the snubber roll 62 is engaged only while the film is to be incrementally advanced onto the takeup reel. When the film is rewound onto the supply reel, the snubber roll 62 is disengaged and acts as an idler. As will appear, that may occur either during the processing of the film while rewinding, or during subsequent rewinding of the processed film after projection.

The film processing means will next be described, in its presently preferred embodiment, with reference first to FIG. 5. As there shown, the apparatus generally comprises wall means comprising portions of, or formed integral with, the base plate 47 and the cover plate 50, which serve to guide, support and house the various elements of the processing apparatus to be described. These walls form an outer film composition containing housing generally designated 83, defining a chamber in which there is mounted an initially sealed container generally designated 84 of processing composition. The container 83 communicates with a coating nozzle generally designated 85. These elements are mounted above the plane of the film 26.

Principally located below, but in part surrounding, the film 26 is a pressure pad generally designated 86. The/pressure pad is actuated on by a spring, generally designated 87 and to be described in detail below.

The basic elements of the processing station further comprise a combined pressure pad deflection cam and nozzle closure valve assembly generally designated 88, and a pair of electrical terminals 58 and 59. The terminals 58 and 59 cooperate with the cam and valve assembly 88 in a manner to be described below to provide a signal indicating whether or not the film 26 has been processed.

More specifically, the outer container 83 comprises walls 89 formed integral with the floor plate 47 and extending upwardly therefrom in FIG. 5. The walls 89 and floor plate 47 form a container open on a side that is closed by a cover panel fragmentarily shown at 90 of the same general configuration as the region bounded by the walls 89 of the container 83.

The panel 90 is preferably put in place prior to assembly of the cover 49 with the base 45, and serves as a support for the top plate 50 after final assembly. As schematically indicated, the walls 89 are formed with an upper lug 91, and a lower ledge portion 92, in each of which are formed locating recesses 93 and 94, respectively, adapted to receive corresponding locating posts, not shown, formed on the inside of the cover panel 90 to aid in locating the panel 90 during its installation as the cover of the container 83.

The initially sealed container 84, mounted within the outer container 83, comprises a tub-like receptacle 95,

of a suitable plastic or the like, selected to resist interaction with the processing composition, or permeation thereof by ambient gases. The receptacle 95 initially contains a charge 96 of processing composition in an adequate amount to process the film 26.

The receptacle 95 is formed on an open side with a circumscribing flange 97 adapted to fit into corresponding slots formed in the base plate 47 and the cover panel 50. As shown in FIG. 5, the flange 97 rests against a shoulder formed on the lug 91 at the upper end of the wall 89, and projects over the ledge 92 formed at the lower end of the wall 89.

The container 84 is sealed to initially contain the processing composition 96 by one end 98 of a tear-tab generally designated 99. The tear-tab 99 may be made of any suitable form of plastic material selected to resist the action of the composition 96, and to avoid interaction therewith, as well as to prevent the diffusion into the composition of gases such as oxygen, carbon dioxide, carbon monoxide, water, oxides or hydrides of sulfur or nitrogen, or the like, that might modify its composition. The end 98 is sealed to the plane surface of the flange 97 surrounding the opening formed in the receptacle 95, and within the flange area extending into the mounting recesses described above, by any suitable means such as heat sealing, by a suitable adhesive, or the like.

The tear-tab 99 extends from the end 98 sealed to the receptacle 95 back upon itself and out through an aperture 100formed in the walls 72 to the processing composition release mechanism, to be described below.

utside of the sealed container 84, the walls 89 de fine a chamber 101 into which the processing composition 96 can flow when the tear-tab 99 is partially detached from the receptacle 95 in a manner to be described. The outer chamber 101 communicates with the coating nozzle 85 by way of a downwardly converging section 102 that communicateswith a downwardly converging inlet passage formed in the nozzle 85.

Referring now to FIGS. 5, l and 16, the coating n02 zle 85 may be formed in a conventional manner, as by precision molding or the like, from a suitable thermoplastic resin selected to form a dimensionally stable and accurate molding whose working surfaces can be kept to close tolerances. The most critical of these form a plane, generally U-shaped film engaging land 103 formed on the base of the nozzle, as best shown in FIG. 15, and a doctor bar 104, lying across the bend of the U-shaped land 103, and recessed beneath it as best shown in FIG. 16.

The depth to which the doctor bar is recessed is greatly exaggerated in FIGS. and 16; it is selected to be twice the desired thickness to which the coating composition is applied to the film 26. The land 103 and the doctor bar 104 circumscribe a generally rectangular outlet aperture 105 formed in the nozzle and communicating with the downwardly converging passageway 106 through which the processing-composition is received from the outer container 83, described above.

The nozzle 85 is formed to be received in cooperating slots formed in the housing parts, to hold it in the position shown in FIG. 5. Referring to FIGS. 5 and 15, the ends 107 and 108 of the nozzle engage corresponding notches 109 and 110 formed in an extension 111 of the wall 75, and in the ledge 92, respectively, to receive the nozzle 85. The sides 112 and 113 of the nozzle 85 are retained by the base plate 47 and cover plate 50 of the housing.

The nozzle 85 is provided at the sides with posts 114 and 115 that provide guidance for the film in its path over the coating gap. These posts also serve at times to stop the nozzle closure plate portion of the element 88, to be described. Referring now to FIG. 15, when engaged with the film in the manner to be described below, the film is adapted to pass over the nozzle outlet port and between the posts 114 and 115, with the emulsion side of the film in engagement with the land 103. During this engagement, coating takes place while the film moves, so that the emulsion surface leaves the aperture 105 as it passes over the doctor bar 104 and carries with it a coating of processing composition established by the depth to which the bar 104 is recessed below the land 103.

Referring again to FIG. 5, and also to FIG. 13, the pressure pad 86 will next be described. The pressure pad 86 is shown in FIG. 5 in the initial position assumed upon assembly of the cassette and prior to processing of the film 26.

As shown in FIG. 5, the film 26 normally passes below the nozzle 85,and above a normally disengaged film engaging pad surface 116. The pad surface is formed on an upwardly extending and generally rectangular protrusion in a base plate 117, as best'shown in FIG. 13. The pressure pad 86 may be made of anysuitable conventional material, such as stainless steel or the like. The raised surface 1 16, formed by die stamping or the like, is ground or otherwise finished with a film engaging plane surface 1 18, of generally U-shaped configuration as illustrated in FIG. 13, that is adapted to mate, through thefilm 26, with the plane of the land 103 of the nozzle (FIGS. 15 and 16) and generally conform to the-working area of the, nozzle 85 confined between the land 103 and the doctor bar 104 and encom-.

The pressure pad 86 is formed at its other end with I a pair of upstanding ears 121 formed integral with the plate 117 and extending upwardly past the film in FIG. 5 to engage a sloping ledge 122 formed in the lower side of an extension 123 of the walls and 89. The extension 123 is formed integral with the base plate 47 and joins the wall 75 defining the projection aperture.

Referring again to FIG. 5, the ears121 initially hold the film engaging surface 116 of the pressure pad out of engagement with the film. As will appear, the ears 121 of the pressure pad also serve at times as guides for the combined pressure pad depressing cam and nozzle closure plate assembly88, to be described.

The base plate 117 of the pressure pad is divided to form a pair of legs 124 which are bent downwardly somewhat in the region of theears 121 as suggested in FIG. 14. Between the legs 124 is formed a downwardly depending hook element 125 that initially serves as a detent to hold the pressure pad 86 in an inactive position in the housing. For that purpose, as best shown in FIG. 5, the hook 125 is engaged in the initial position shown by an upwardly bend end l26formed at the end of the spring 87.

As shown in FIG. 5, the spring 87 comprises a base portion 127 that is cut out to clear a bearing post 128 on which theidler roll 57 is journalled. The base portion 127 is further provided with a pair of mounting apertures in which suitable fasteners, shown as a pair of screws 129 in FIG. 5, can pass for securing the base 127 to the base plate 47. In practice, the base 127 of the spring 87 may be secured by heat staking it to the thermoplastic material of the-base plate 47, as by heating and melting a portion of the base plate 47 through the with the film-engaging portion of the pressure'pad 86,

and thence to its termination 126 initially engaged with the hook 125. Intermediate the ends of the arm 130 is formed apressure pad engaging button 131, fragmentarily shown in FIG. 10, that serves to engage the lower surface of the raised portion 116 of the pressure pad 86 and urge it toward engagement with the film 26.

Referring now to FIG. 5 in conjunc'tionwith FIGS. 17 and 18, the pressure pad depressing cam and nozzle closure plate assembly 88 will next be described. Referring first to FIGS. 16' and 17, the assembly 88 comprises a plane base plate 132 formed at one end 133 with tapering sides 134 to guide entry of the end 133 into a position covering the outletport 105 in the nozzle 85, in a manner to appear, to close the nozzle at the end of the processing operation. In that position, a pair of shoulders 135 on the plate 132 cooperate with the posts 114 and 115 on the nozzle 85 to stop the nozzle in its final position.

Formed as orthogonal extensions on the sides of the base plate 132 are a pair of cams 136 and 137 that serve at times to depress the pressure pad, described above, in a manner to appear below. The cam 137 is shorter than the cam 136, to facilitate threading of the film 26 during assembly of the cassette. I v

Toward the left end of the plate 132, as best shown in FIGS. 16 and 17, the cam 136 is formed with a normally extending arm 140 that extends generally parallel to the plate 132 and is formed with a pair of spring arm extensions 141 and 142. These arm extensions taper away from each other towards the ends, to allow entry of a film aperture in a manner to appear.

A central portion 143 is bent upwardly and away from leg extension portions 145 of the base plate 132, as best shown in FIG. 17, to form a hook having as its upper portion the extension 143 and as its lower portion the arms 145. Referring again to FIG. 5, these hook elements initially engage a ledge portion 146 formed integral with the base plate 47 to hold the assembly 88 in the position shown. In that position, the earns 1 36 and 137 extend into and are guided by the ears 121, and the nozzle closing plate 'end 133 of the assembly 88 confronts but does not engage a downwardly sloping guide ledge 147 formed on the wall ex tension 111 referred to above.

The upper spring arm 141, of the hook comprising that arm and the lower arm 142 formed on the assembly 88, lightly engages the base of the film 26 in the initial position of the parts shown in FIG. 5. The upwardly bent end of the arm 141 thus serves as a unidirectional detent that is adapted to engage an aperture in the film, in a manner to be described below, towards the'end of the processing cycle to be described.

The cam portion 136 of the assembly 88, of metallic conducting material, cooperates with contacts 148 and 149 formed integral with the terminals 58 and 59, respectively (FIG. 5), to form a signal generator indicating whether or not the film 26 has been processed. For this purpose, in the initial position of the parts shown in FIG. 5 assumed before the processing cycle is started, the cam 136 engages both contacts 148 and 149 and thus bridges them to supply an external signal, in the form of a closed circuit path, to the terminals 58 and 59, indicating to the film drive and projection apparatus, to be described, that the film is not processed.

As will appear, at the end of the processing cycle the assembly 88 will be carried to the right in FIG. 5, opening the contacts 148 and 149 to cause an open circuit to be presented to the terminals 58 and 59, indicating that the film has been processed.

The construction of the processing composition release mechanism will next be described with reference to FIGS. 5, 6, 7, 8, and 9. As shown in FIG. 5, the teartab 99 extends out through the aperture in the outer container 83 and thence over an idler 150 jour-' nalled for rotation in the housing by means schematically shown as a bearing post 151 formed integral with the base plate 47. The tear-tab 99 passes from the idler 150 about another idler, here shown simply as a post 152 formed integral with the floor plate 47.

A loop 153 is formed on the end of the tear-tab 99, as by folding the tear-tab back upon itself and there securing it by heat sealing, or by a suitable adhesive or the like. The loop 153 engages a pin 154 forming a part of the tear-tab release mechanism.

As best shown in FIG. 6, the pin 154 is adapted to be guided in tracks formed as grooves 155 in the cover plate 50, and 156 in the floor plate 47. These tracks form generally parallel spiral path segments that guide the post 154 along a path generally radially outward from the center of the supply spool 51, from the initial position shown in FIG. 5 to the position shown in FIG. 9.

The pin 154 is joined to a post 157 connected to or formed integral with the arm 55 described above. For this purpose, a pair of struts 158 and 159, of steel wire or the like, are connected at their ends to the pin 154 and post 157 as shown in FIG. 6, to form a generally rectangular sled having one end that travels along a radius determined by the arm 55, and a second end formed by the pin 154 that travels in the tracks 155 and 156;

A resilient catch generally designated 160 is connected at one end to the sled just described. The catch 160 may be formed of resilient material such as spring steel or the like,and has one end 161 bent around and engaging the post 157.

The catch 160 extends from the end 161 over an arm 162 formed with outwardly diverging ears 163 and .164. The ear 163 is bent over and thereby secured to the strut 158, and the ear 164 is bent over and thereby secured to the strut 159. The arm 162 is bent at its other end to form an actuator engaging ledge 165.

The ledge 165 extends to an integral hook portion 166. The hook 166 is initially engaged by a detent pin 167 forming part of a tear-tab release enabling mechanism, to be described.

As will appear, upon removal of the pin 167, the arm 162 is free to move under the influence of its initial bias to carry the hook 166 into engagement with the pin 154, whereupon the ledge 165 will be moved into position to engage one of a series of teeth 168 formed about the periphery of the flange 52 of the supply reel 51. As best shown in FIG. 6, the supply reel 51 is provided with a lower flange 169 upon which corresponding teeth 170, in vertical registry'with the teeth 168, are formed.

As shown in FIG. 5, the teeth such as 168 each comprise a slowly radially rising portion 171, and a rapidly radially falling portion that is adapted to engage the ledge 165 when the ledge is released by release of the pin 167, as described above, and when the reel is rotated clockwise in FIG. 5. In the position of the parts shown in FIG. 5, the ledge 165 is held out of engagement with the teeth 168. Upon release of the hook 166, the ledge 165 will engage the rims of the spool 51, whereupon in response to counterclockwise rotation of the spool as shown in FIG. 5, the ledge will simply be deflected by the slowly rising portions such as 171 of the teeth 168. However, upon clockwise rotation, one of the teeth 168 will be caught upon the ledge and carry the sled along the tracks 155 and 156, moving the teartab 99 and at least partially detaching it from the receptacle 95 to release the composition 96. When the sled is thus moved, to the position shown in FIG. 9, the post 154 will be engaged by a resilient detent 172 secured to an extension 123 of the wall 75, latching the mechanism in the position shown in FIG. 9, with the ledge 165 then permanently out of engagement with the teeth 168. i

The release enabling mechanism comprising the pin 167 will next be described with reference to FIGS. 6, 7 and 8. As best shown in FIG. 7, the mechanism comprises a post 175 accessible at one end through the opening 16 in the cover plate 50. A lighttight seal is formed about this aperture 16 by means of a cylindrical flange 176 formed integral with the cover plate 50, and extending between the post 175 and a concentric cylindrical flange 177 formed integral with the post 175.

At its lower end, the post 175 isformed with a coaxial central cylindrical recess 178, which receives a compression spring 179. The spring 179 engages the base plate 47, and is surrounded by a cylindrical annular flange 180 in which the post 175 is guidingly received. The post 175 is thus urged into the position shown in FIG. 7 by the spring 179..It is adapted to bemoved into the position shown in FIG. 8 by a locating pin 181, forming a part of the film drive and projection system to be described, that enters-the port 16 to depress the i post 175 under conditions to be described below.

The detent pin 167 is formed integral with an extension 182 of the post 175 as shown in FIGS. 7 and 8. The extension 182 is adapted to rest against the loop 153 formed on the end of the tear-tab 99, and therethrough to engage and be supported by the pin154 in the initial position of the parts shown in FIGS. 5 and 6.

When the locating pin 181 enters the opening 16 to move the post 175 to the position shown in FIG. 8, the

hook'166'is freed to move into engagement with the pin 154, through the loop 153. The sled including the pin 154 is thereafter free to move out of engagement with the extension 182 formed on the post 175.

Having described one embodiment of the cassette of the invention, its operation will next be described in connection with FIGS. 4-12.

Referring to FIG. 5, it will be assumed that an initially unexposed strip of film 26 stored primarily on a supply reel 51 has been exposed in a camera, so that it has been advanced onto the takeup reel 63 to the exposure termination point determined by the first elongated sprocket hole 39 in the film (FIG. 4). The tear-tab 99 and its release mechanism will be in the positions shown in FIG. 5, with the post 175 in the position shown in FIG. 7, in which the pin 167 engages the hook 166 to hold the catch ledge 165 out of engagement with the rims of the supply reel.

Next, assume that operation continues by the insertion of the locating pin 181 into the port 16 ofthe cassette. As shown in FIGS. 7 and 8, entry of. the pin 181 will depress the post 175, releasing the pin 167 and allowing the hook 166 to travel into engagement with the loop 153 on the tear-tab 99, and, therethrough, with the pin 154. Referring again to FIG. 5, the ledge 165 will now be moved into position to engage the teeth such as 168 formed on the supply reel 51.

Next, assume that operation is continued by further rotation of the takeup reel 63 counterclockwise, as

seen in FIG. 5, to bring the film 26 farther onto the takeup reel. During this rotation, the supply reel 51 will move counterclockwisein :FIG. 5, causing the teethv 168 to pass the ledge 165 without effective engagement therewith.

FIG. 5 shows the parts of the coating station in their initial position, which is maintained during exposure of the film and during a portion of the first increment of motion just described, from the exposure termination point toward the second termination point in which the film is substantially exhausted from the supply reel, and in which the second elongated sprocket hole 40 in FIG. 4 will be encountered. During the interval of travel between those positions, and prior thereto, the cam and nozzle closure plate assembly 88 is held in place by engagement of the arms 143 and 145 with the ledge 146, and the upper resilient arm 141 of the film engaging hook formed on the assembly 88 is lightly engaging the base of the film 26.

The pressure pad 86 is initially held in place by engagement of its hook 125 with the detent 126 formed on the spring 87. In that position, the end 119 of the pressure pad 86 lightly engages the base of the film 26, and the ears 121 are in engagement with the ledge 122 formed on the wall segment 123.

The parts of the coating station will remain in the position shown in FIG. 5 until, during the further advance of the film 26 towards the takeup reel, the film engaging hook 43 approaches and engages the end 119 formed on the pressure pad 86 as shown in FIG. 10. When that occurs, near the second termination point established by the second elongated hole 40 in the film (FIG. 4), the hook 43 will move the pressure pad to the left in FIG. 10, to the position shown, in which the ears 121 have moved out of engagement with the ledge 122, and upwardly under the influence of the spring 87. The ears 120 on the pressure pad 86 will come into engagement with the posts 114 and forming a part of the nozzle 85, and the pressure pad 86 will swing up into engagement with the film 26 and carry the emulsion side of the film into coating engagement with the nozzle 85.

Next, assume that the first rewind operation is begun, by rotating the supply reel 51 clockwise in FIG. 5, to advance the teeth such as 168 towards the ledge 165 on the latch 160. Referring to FIG. 11, this motion will bring the hook 43 out of engagement with the end 119 of the pressure pad 86, as shown. The pressure pad will now urge the film 26 into coating engagement with the nozzle 85 under the influence of the spring 87.

As the pressure pad 86 is moved to the left, the detent 126 formed on the spring 87 will be disengaged by the hook 125. The purpose of the detent 126 is primarily to prevent premature movement of the pressure pad 86 in the housing prior to its positive disengagement from the initial position shown in FIG. by the hook 43. l

Referring next to FIGS. 5, 6, and 9, as the film 26 moves towards the supply reel 63, a pair of teeth 168 and 170 on the supply reel will engage the ledge 165, and the latch 160 will carry the sled comprising the pin 154 to the position shown in FIG. 9, detaching the teartab 99 in part from the receptacle 95 to allow the composition 96 to flow down into coating engagement with the nozzle and the film 26. The composition will then be uniformly coated on the emulsion side of the film 26 to a thickness determined by the doctor bar 104.

A doctor bar coater is preferred to other conventional forms of coaters for the purpose of coating the film, because it is inherently insensitive to changes in the viscosity of the processing composition, and to changes in linear film speed with respect to the doctor bar, over a reasonable range that makes the process relatively insensitive to these variables. Inparticular, as is well known in the art in other contexts, a doctor blade or doctor bar coater inherently will lay down a uniform coating of one-half the distance between the'doctor bar and the coated substrate under conditions in which a uniform meniscus can be formed on the coating liquid adjacent its interface with the substrate.

Thecoatingoperation begun with the parts in the position shown in FIG. will continue until the composi-- tion 96 is substantially exhausted and the film is stored substantially all on the supply reel 63. Toward the end of that operation, the aperture 44 (FIG. 4) will approach and engage the hook finger 141 formed on the valve and cam assembly 88.

As the film 26 continues to move onto the supply reel, engagement of the aperture 44 in the film with the spring arm 141 will carry the film along the arm and downwardly, as suggested in FIG. 11, into the bight formed between the arms 1'41 and 142. Further movement of the film 26 towards the supply reel will carry the cam and valve member 88 to the right of the position shown in FIG. 11, causing the spring arms 143 and 145 to disengage the ledge 146, and bringing the cams 136 and 137 into contact with thebase plate 117 of the pressure pad 86 in the region of the ears 121, with the cam assembly '88 being guided by the ears 121, as the assembly '88 moves to the position shown in FIG. 12.

During this movement, the end 133 of the cam and valve assembly 88 is guided by the ledge 147 formed on the wall extension 111 of the housing, and moves below the nozzle 85 towards a nozzle closing position. The pressure pad 86 begins to move downwardly, out of engagement with the film 26. The film is still held down out of its normal plane of movement by engagement with the bight formed between the spring arms 141 and Movement in this direction will continue to move the assembly 88 to the right, as it goes to the position shown in FIG. 12 in which the end 133 of the valve assembly 88 closes the nozzle and the shoulders formed on the assembly 88 engage the stops 114 and 115 formed on the nozzle 85. The lower spring arm 142 glides over and engages a stop 183, which may conveniently be formed integrally with the cover wall, to latch the cam assembly 86 against movement to the left as shown in FIG. 12.

During its movement from the position shown in FIG. 11 to the position shown in FIG. 12, the cam 136 disengages the contacts 148 and 149, and thus provides a signal indicating that the film has been processed.

FIG. 12 shows the final disengaged position of the processor parts, with the film 26 out of engagement with the hook elements 141 and 142. This position is attained when the film is again moved toward the takeup reel, as during projection of the processed film. When that occurs, the aperture 44 will disengage the arm 141, and the filmwill rise to its initial plane of movement, in which it is free of all of the elements of the processing apparatus, for subsequent cycles of projection and rewinding.

The nozzle 85 is now closed except for the small passage between the doctor bar and the upper surface of the valve end 133 of the assembly 88. Since this is quite a small aperture, on the order of several tenthousandths of an inch, it will quickly be sealed by the evaporation of the vehicle from the processing composition, with concomitant drying and hardening of the composition in the gap. Contamination of the apparatus is further prevented by the fact that any leakage of processing composition that may occur will be primarily upon the upper surface of the end 133 of the assembly 88, where it will be exposed to drying without further contact with the film.

, Further details of the film drive and projection system will next be described, with reference first to FIG. 18. As there shown, the film drive and projection system comprises a control system generally designated which is adapted to be operatively associated with a cassette 1 when the latter is inserted into the pocket 2 of the film drive and projection system of FIG. 1.

The control system 185 provides energy over a lead 186 to drive a conventional alternating current motor ACM. The motor ACM has an output shaft 188 that drives a conventional blower fan 189. The fan 189 provides forced air for cooling a projection lamp, to be described. The shaft 188 also drives the input side of a conventional electromagnetic clutch EK. The clutch EK is engaged when a clutch magnet CM is energized by current supplied over a lead 187 from the control system 185.

When engaged, the clutch EK drives a shaft 190. A crank generally designated 191 is connected to the shaft to reciprocate a film advance pawl 192. The film advance pawl 192 may be conventional, except that it is formed with two spaced film engaging teeth that serve to engage two of the sprocket holes 38 in FIG. 4. When the first elongated sprocket hole 39 is reached, one of these pawls serves to continue driving the film until the second elongated sprocket hole 40 is encountered. The dual pawl will fail to engage the film when it encounters this hole 40, and film advance will terminate. v

The shaft 190 also drives the shutter 9, through conventional means here shown schematically as a bevel gear 193 engaging a bevel gear 194. A gear 195 is fixed to the gear 194, and drives a gear 196 to cause operation of the conventional rotary shutter 9. The shutter 9 is thus synchronized with the film drive pawl 192 in a conventional manner, whereby processed images on the film can be sequentially projected.

A conventional DC motor DCM is at times energized by current supplied over leads 198 and 199 from the control system 185. The motor DCM drives a shaft 200. On the shaft 200 there is fixed a set of ferromagnetic vanes 201, which rotate past a conventional magnetic reed switch SF to open and close its contacts repeatedly when the shaftv200 is rotated. This switch SF serves toprovide speed feedback control for the motor DCM, in a manner to appear.

The shaft 200 drives two oppositely oriented one-way clutches CKl and CK2. Upon rotation of the shaft 200 in one direction, the clutch CKl will be engaged to drive a shaft 202. The shaft 202 drives a shaft 203 through a conventional slip clutch SKI. The shaft 203 also drives a second set of ferromagnetic vanes 204 past a conventional magnetic reed switch SM. The contacts of the switch SM arethus repeatedly opened and closed when the shaft 203 rotates. The switch SM is used to detect motion of the shaft 203, as will appear. The shaft 203 drives a sprocket 205 that is adapted to engage the drive sprocket 65 of the takeup reel.

When the motor shaft 200 is rotated in the opposite direction, the clutch CK2 is engaged to drive an output shaft 206. The shaft 206 drives a shaft 207 through a conventional slip clutch SKZ. The shaft 207 is connected toa drive sprocket 208 that is adapted to engage the drive sprocket 53 of the supply reel.

It' will be apparent that in the apparatus just described, when the motor DCM is operated in one direction, the takeup spool drive sprocket 65 will be driven. That will cause rotation of the supply sprocket 53, through the film interconnecting the takeup and supply reels. When the motor is rotated in the other direction, the supply reel sprocket'53 will be driven, causing rota tion of the takeup reel drive sprocket 65 through the film. In either case, the shaft 203 will be rotated to.

cause the vanes 204 to repeatedly open and close the switch SM.

A snubber stop 209 is at times driven into engagement with the hub 82 of the snubber roll, described above. That action occurs under the direction of the control system 185, in a manner to appear. Similarly, the locator pin 181 is at times caused to enter the port 16 in the cassette 1, under the control of the control system 185.

The terminals 58 and 59 on the cassette 1 are adapted to engage a pair of contacts 210 and 211, respectively, connected to the control system 185. These contacts sense whether or not the film in the cassette 1 has been processed, for purposes to appear.

The control system 185 at times provides current over a lead 212 to energize a projection lamp K1. When energized, the lamp Kl supplies light through the port 14, to cause projection of images on the film in the cassette 1. In addition to the projection lamp K1, the

control system at times energizes two indicator lamps K2 and K3, for purposes to appear.

The sequence of operations of the apparatus is determined by the setting of eight selector switches, S1, ST, SD, SP, SR, MR, SJ and SE. As will appear, the switch S1 supplies power to the apparatus. It remains closed during operation of the system. The switch ST is closed during the interval in which it is desired to advance the film from the exposure termination point established in the camera to the second termination point established by the second elongated sprocket hole 40 in FIG. 4. Following that advance, the switch ST is opened, and the switch SD is closed, to cause processing rewind in a programmed manner to be described. At the end of that cycle of operation, the switch SD is opened, and the switchSP is closed to cause processed images on the film in the cassette 1 to be projected. Following projection of the film, the switch SP is opened, and the switch SR is closed to cause rapid rewind of the film onto the supply reel. Finally, the switch SE is closed momentarily to cause ejectionof the cassette.

A motor reversing switch MR is provided that selectsthe direction of operation of the motor DCM in a manner to appear. Between operations of the motor DCM, a switch SJ is depressed momentarily, to clear a motion detector circuit to be described and condition it for the subsequent operation to follow.

As described above, it is desired to program the first rewinding operation of the film by driving the supply reel in two steps separated by a waiting interval. ln the first step, a short section of the film is taken back onto the supply reel to cause rotation of the supply reel in a directionthat will release the tear-tab in the manner described above. Following the partial detachment of the tear-tab from the initially sealed container of pro cessing fluid, a short interval is allowed to elapse during which the film is not moved in order to give the processing composition time to flow down into the nozzle. Thereafter, it is desired to move the film 26 at constant linear speed past the processing station over substantially the full length of the film. A number of factors, including primarily the fact that the film radius on the supply reel changesas it is wound onto the supply reel, makes it undesirable to drive the supply reel at constant speed during rewind. Rather, the supply reel should be driven at such a speed that the linear speed of the film past the processing station is constant. The manner in which this function can be accomplished will next be discussed. I

The velocity u of the film past the processing station, is given by where u is velocity in inches/second, r is the radius of the film on the supply reel in inches, and w is the angular velocity of the supply reel in radians/second.

The radius r at any time t is given by r= r0 (s/21r) f wdt where r0 is the initial radius, s is film thickness in inches, and t is the time in seconds.

From (1) and (2), 

1. Photographic apparatus for moving a strip of film past a processing station at constant speed, comprising a reel connected to one end of said strip and mounted for rotation in fixed relation to said processing station to wind said film onto said reel and advance it past said processing station when said reel is rotated, drive means connected to said reel and responsive to a source of energy for rotating the reel at an angular velocity determined by the amount of energy supplied thereto, and preprogrammed means for supplying energy to said drive means in predetermined amounts progressively changing in dependence on the amount of the film on the reel at any time during winding and selected to cause the film to move past the processing station at constant speed, in which said drive means is an electric motor and said preprogrammed means comprises circuit means for producing an exponentially decaying electrical signal and means responsive to said signal for supplying current to said motor in an amount proportional to the amplitude of said signal.
 2. Photographic apparatus for moving a strip of film of predetermined length and thickness past a processing station at constant speed, comprising a reel connected to a first end of said strip and mounted for rotation about an axis at a predetermined distance from said first end and in fixed relation to said processing station to wind said film onto said reel and advance it past said processing station when said reel is rotated, drive means connected to said reel and responsive to applied energy for rotating the reel at an angular velocity determined by the amount of energy supplied, and preprogrammed means for supplying energy to said drive means in predetermined amounts progressively changing in dependence on the radius of said strip on said reel at any time during winding and selected to cause the film to move past the processing station at constant speed, in which said drive means is an electric motor and said preprogrammed means comprises circuit means for producing an exponentially decaying electrical signal and means responsive to said signal for supplying current to said motor in an amount proportional to the amplitude of said signal.
 3. The apparatus of claim 2 in which said circuit means comprises a capacitor, means for charging said capacitor to a predetermined voltage, and a discharge circuit for said capacitor having a predetermined resistance, said signal being determined by the voltage across said capacitor as it is discharged through said resistance. 